Prosthetic acetabular hip cup assemblies are well known in the field of orthopaedic surgery. Acetabular hip cup assemblies having elevated rims are also well known in the art. Examples of prior art acetabular hip cup assemblies with elevated rims and attached by snap rings are illustrated in the following U.S. patents:
Engelhardt, et al. U.S. Pat. No. 5,049,158 discloses an acetabular cup assembly having a bearing component and a metal acetabular cup component held in a locked relationship by a wire formed about the periphery of the bearing component. The bearing component includes an elevated rim which contacts the rim of the metal cup.
Forte, et al. U.S. Pat. No. 4,695,282 disclosed an acetabular cup assembly having a bearing component and a metal cup. The bearing component may be temporarily positioned within the cup prior to locking engagement to permit the surgeon to check the orientation of the cup and bearing component. To lock the two components together, the bearing component is pressed further into the cup wherein a locking ring engages the cup. When locked, the elevated rim of the bearing component contacts the rim of the cup.
Parchinski U.S. Pat. No. 4,650,491 discloses an acetabular cup assembly wherein the bearing component includes a plurality of rings which engage a groove in the metal cup to lock the two components together. In use the elevated rim of the bearing component contacts the rim of the metal cup.
During a procedure to implant the prosthetic acetabulum and hip stem, to reduce the joint the surgeon must negotiate around the elevated rim to seat the femoral head within the bearing component.